Field of the Invention
This invention relates to a new and improved induction cooking unit capable of safe operation with metal base pans of all types having a wide range control of the power level at which the induction cooking unit operates.
More particularly, the invention relates to an improved induction cooking unit of the type intended for use with kitchen ranges having a cool insulating top surface. At least one pancake-shaped planar induction heating coil disposed below the insulating surface and produces magnetic lines of flux that are coupled to a pan or other metal base cooking vessel placed on the insulating surface over the coil. The coil is excited by high frequency currents supplied to the coil by an improved chopper inverter supply constructed in accordance the present invention, and which makes it possible to operate safely metal-base cookware of all types including highly conductive aluminum, copper and other pans without endangering the induction cooking unit. Further the unit may be operated safely over a wide range of power levels including quite low power levels, of the order of 1/24 of the maximum level of power available from the unit.